New insights into Ross Ice Shelf stability over broad timescales from high-resolution ROSETTA-Ice survey
Abstract
The processes governing ice shelf stability operate across a spectrum of timescales, from tides to multi-millennial cycles of glacial advance and retreat. Modern observations of ice-shelf change span at most a few decades, shorter than the societally-relevant time scale of roughly a century over which we expect Antarctica's changing role on global climate and sea level rise to become substantial. The short duration of the observational record implies that we cannot even be confident that the most critical ice shelves in future will be those that are presently changing rapidly. Models accommodating timescales of past glacial cycles are needed to reconstruct the conditions observed from the paleo-record, and to understand processes that control long-term ice shelf stability.
By a combined, interdisciplinary study of earth, ice, ocean and atmosphere the ROSETTA-Ice project seeks to understand the interrelated processes that govern the stability of the Ross Ice Shelf, and the timescales over which their influence dominates. Initial findings of the project documented the long-term influence of bathymetry on ocean circulation from the tectonically-controlled asymmetry of the sub-ice-shelf cavity, and the short-term risks to ice shelf stability controlled by seasonal upper-ocean ocean warming and ice shelf thickness. Here, we focus on the implications of the newly-resolved 5-10 km length-scale bathymetry revealed from combined gravity and magnetic modelling of the full ROSETTA-Ice survey, and ice draft and internal ice structure from radar soundings. Near the ice front, small-scale bathymetric features are depositional and erosional structures that developed during previous glacial cycles, and now guide the intrusion of modified Circumpolar Deep Water (mCDW) into the ice shelf cavity. Understanding the age, origin and extent of these time-dependent features is essential to reconstructing the past influence of mCDW on the Ross Ice Shelf system and to predicting its future.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C13A..01T
- Keywords:
-
- 0720 Glaciers;
- CRYOSPHERE;
- 0726 Ice sheets;
- CRYOSPHERE;
- 0728 Ice shelves;
- CRYOSPHERE;
- 4207 Arctic and Antarctic oceanography;
- OCEANOGRAPHY: GENERAL